1. Technical Field
This invention relates to an automatic plant selector that is adapted to minimize the transplant of non-viable seedlings.
2. Background Art
There are various problems associated with automatic transplant devices. Some of these problems are related to the configuration of the transplant device, while other problems are related to the manner in which seedlings are selected for transplant.
By way of background, a practice widely used in agriculture is that plants are grown in nursery trays to a height of 3 to 5 inches, at which point they are transplanted into a field where they are grown to maturity. Various transplant machines are available that will put a plant into the ground at the correct spacing, however, most of these machines require that a person be seated on the transplant machine to manually take one plant at a time from a nursery tray and place it into the transplant machine. Other machines are available which will automatically place plants into the transplant machine. However, these automatic plant selector machines are plagued with the problem of placing non-viable or "blank" seedlings into the transplant machine. The transplant of blanks into a field serves to significantly limit crop yields as the remaining viable seedlings grow to maturity. While using human labor to provide seedlings to a transplant machine can significantly reduce the incidence of blanks, the cost of such labor can be prohibitive.
Plant selectors used with automatic transplant devices use single nursery trays that are indexed, or moved in steps in the X-Y plane, such that cells in the tray become available, in turn, to a plant removal mechanism. The plant removal mechanism removes seedlings from the tray and provides them either singly, or in groups, to the automatic transplant device for transplanting into a field. Many of these devices ignore the presence of blank or non-viable cells. Other devices may use sensors to determine whether a viable seedling has been selected. Such devices may attempt to select an alternate seedling from the nursery tray to replace a non-viable seedling. However, indexing the tray to provide alternate seedlings to the plant removal device may require the transplant machine to slow or stop while an alternate is selected.
Therefore, in order to overcome the limitations of prior transplant devices, what is needed is a device that will eliminate the requirement of human labor by automatically providing seedlings to an automatic transplant device. In addition, this device should significantly limit the incidence of blank transplants by ensuring that the seedlings provided to the automatic transplant device are viable. Further, the selection of viable seedlings should not require the automatic transplant device to wait for an alternate seedling when the plant removal mechanism encounters a non-viable or blank cell in the nursery tray.